Process of mixing concrete and other plastics



Aug. 26, 1924. 1,506,143

R. C. STUBBS PROCESS OF MIXING CONCRETE AND OTHER PLASTICS Filed Jan. 23. 1923 Patented Aug. 26, 1924.

UNITED STATES ROBERT C. STUBBS,

or DALLAS, TEXAS.

PROCESS OF MIXING CONCRETE AND OTHER ILASTICS.

Application filed January 23, 1923. Serial No. 614,889.

To all wlwm it may concern:

Be it known that I, ROBERT C. STUBBs, a citizen of the United States, residing at Dallas, in the county of Dallas and State of Texas, have invented certain new and useful Improvements in Processes of Mixing Concrete and Other Plastics, of which the following is a specification.

My invention relates to a process of mixing concrete and other plastic material; and 1 the objectis to provide a process of mixing concrete under pressure and by such process to improve the grade of such plastic materials and to provide a process of mixing plastics at less ex ense than the old processes. Another 0 ject is to mix concrete under sufficient pressure to overcome gravity so that the mortar portion will be uninfluenced by gravity and will be forced among and upon the surfaces of the large aggregate of the mass so that the binder elements are made to cling to or on all the surfaces of the large aggregate and when so mixedthere will be less space for air and surplus moisture. Other objects and advantages will be fully explained in the following description and the invention will be more particularly pointed out in the claims.

Reference is had to the accompanying drawings for illustration of the process.

Fig. 1 is a longitudinal section of the drum used in the process, showing the interior mechanism. Fig. 2 is a cross-section of the drum, showing an end view of the helical agitators or vanes. Fig. 3 is a broken sectional view, showing the construction of the spiral or helical vanes or agitators. Fig. 4 is a sectionalv view of the drum shaft with its vibrating means.

Similar characters of reference are used to indicate the same parts throughout the several views.

' The usual proportions of sand, cement, stone and water are used in the improved process and for the purpose of accomplishing the object of this invention a drum, preferably cylindrical, is employed and this drum 1 is stationarily mounted and is provided with a closable inlet 2 and a closable discharge opening 3. A hopper 4 may be used to direct material through the inlet opening 2 and a chute 5 may be provided at the discharge opening. A swinging door I sure within the drum 1.

6 is hingedly connected to the discharge end of the drum for closing the discharge opening 3. The door 6 may be held closed by a sliding bolt 7. The opening 2 is closed during a compression and mixing period by a sliding cover 8 which moves through the side of the hopper and in ways 9.

A helical or spiral form of vane is employed for agitating the materials. A shaft 12 projects into the drum 1 and an outer vane 10 and an inner vane 11 are employed and fixedly connected to the shaft 12 and are driven by this shaft. The vanes are rectangular in cross-section, as shown in Fig. 3, and are of appreciable width. The outer vane 10 may be left hand and the inner vane right hand and vice versa. The surface 0 the outer vane slants inwardly slightly and the inner vane slants outwardly slightly and the vanes are made of spring metal so that there will be more or less vibrations given to the materials being mixed. The outer vane throws the material inwardly and towards the discharge end of the drum and the inner vane throws the material outwardly and towards the closed or feeding end of the drum while the shaft 12 drives both vanes in. the same direction. A gear wheel 13 is rigid with the shaft 12 and meshes with a inion 14 which is driven by a motor 15. he construction and arrangement of the vanes cause the vanes to throw the material in opposite directions.

In order to prevent any vacancies in-the material within the drum 1 during operation, a plunger or compressor 16 is employed and more. or less force or power is employed to bear against the compressor 16 to secure the necessary pres:

Sufficient pressure to overcome gravity should be employed. The power to be applied ma be furnished by a spring 17 which will ear against the end of the compressor, or a lever 18 may be used. The spring 17 may be attached to the end of the drum. The lever 18 may be provided with a fulcrum 19 which is mounted on the drum. It is apparent that other means may be used to force the compressor 16 into the drum. The

drum may be withdrawn by a cable 20. I

When. the material has been suflicien mixed, the door 6 will be opened and one material will be forced out of the drum n pressure while the vanes are being rotated. The principal function of the vanes and the compressor is to mix the material or component parts of the material under pressure. When the sand, cement, and stone particles are mixed with water and placed in the drum, they may not quite fill the drum and the mass would not be under the desired pressure, but such mass is capable of being shaped to fill all available space in the drum. Such space will be taken up when pressure is applied to the compressor 16 to force the compressor towards the center of the drum. The material being in a plastic condition, the material will be forced in all directions within the drum.

In order to aid the mixing of the ingredients, provision may be made for vibrating the material by means of the vanes. The shaft 12 is provided with a bearing sleeve 22 which is rigid therewith. The sleeve 12 is journaled in the end of the drum 1 and the shaft 12 is placed slightly off the center of the sleeve 22. When the shaft 12 is driven, the vanes 10 and 11 will be more or less vibrated. This will cause a more thorough mixing and the vanes will be turned more easily in the material by reasono? the vibrations.

When a quantity 'of material has been sufiiciently mixed, the door 6 will be opened and the material will be forced out of the drum by. pressure while the'vanes are being rotated. The principal function of the vanes and the compressor isto mix the material or component parts of the concrete under pressure. Herein lies a great difl'erence between thi improved mixer and the previous mixers. The previous mixers distribute the aggregate but do not force the binder particles onto the surface of the larger aggregate with friction caused by pressure on the same. The usual mixing is done in a loose state of the mass. With the improved process, the mixin is done in a compacted state of the mass. n the usual mixing the discharge must wait until the drum has revolved enough to empty the batch finally. In the improved process, the discharge is forced under pressure at the rate desired. Friction between the particles is required to establish their closest relation and the resulting benefit of the mixing will depend upon the amount of friction applied. *Power is required in securing a mixture of the particles with greatest binding relation and unless considerable power is consumed or applied, little friction will occur between the particles to be bound. The prime object of my discovery is to secure positive contact and final maximum bond between particles of a mass in mixing and in order to accomplish this, the particles must be mixed while the mass is under pressure. The drum 1 will resist outward pressure while the material is constantly moved back and forth in the drum, the central portion moving in one direction and the outer surrounding portion moving in the opposite direction and the two portions being more or less cut into each other by reason of the shape of the two vanes and all vacant space being prevented by the compressor while the mixing is going on. In such'mixi'ng the mortar portion is uninfiuenced by gravity and is forced among and upon the surfaces of the large aggregate of the mass. The material is also vibrated while the mixing is going on' and this adds efficiency to the process.

The process includes means for measuring or determining theamount of water" and other elements and for determining the consistency of the mixture. sented with this specification, but the drawings are only diagrammatic and may be changed to improved devices for carrying out the process.

What I claim is,-

1. A process of mixing concrete or other Drawings are pre--' plastic comprising the moving of the central 2. A process of mixing concrete or other I plastic comprising the moving of the central portion of a plastic mass in one direction and the outer surrounding portion in the opposite direction in a confining vessel and causing'portions of each moving mass to cut into the other moving mass and ap lying movable mechanical pressure to'sai mass for securing frictional contact of the particles on each other.

3. A process of mixing concrete or other plastic comprising the moving of the material in spiral columns in opposite directions in a'confining vessel and appl ing movable pressure means to said mass uring the mixing operation for preventing any vacancy in the vessel and for securing friction of the coarse aggregate particles on each other.

4. A process of mixing concrete or other 'pl'astic comprising the moving of the main a confining vessel and the applying of movable mechanical pressure means to the material during the moving thereof.

6. A process of mixing concrete or other plastic comprising the moving of the particles upon each other and the applying of self-acting mechanical pressure to the whole mass while being moved for expelling entrained air and creating frictional contact of the aggregate for compacting the binding elements thereon.

7. A process of mixing concrete or other plastic comprising a mixing of the ingredients and the confining by application of movable mechanical pressure Within the mass for compacting the same during the mixing of the ingredients.

8. A method of mixing a plastic material aggregate in a confining vessel which consists in mixing the ingredients and simultaneously applying independent non-fluid pressure to the mass to compact the same and expel air therefrom.

9. A method of mixing a plastic material aggregate in a confining vessel which consists in mixin the ingredients and simultaneously applying independent non-fluid pressure to the mass for causing cement mortar to be compacted on the surfaces of the larger aggregate and for compacting the mass and expelling air therefrom.

10. A process of mixing concrete or other plastic material comprising mixing the aggregate and applying a movable comp-ressor Within the mass While being mixedto compact the mass and to expel entrained air therefrom.

In testimony whereof, I set my hand, this 19 day of January, 1923.

ROBERT C. STUBBS, 

